Search The Database

Harbor seals (Phoca vitulina) appeared to habituate to acoustic harassment devices placed on gillnets in the Oregon salmon fishery. Results, although inconclusive, demonstrate a possible reduction in damaged salmon, at least in the short-term.

Although effective in trials with captive loggerhead (Caretta caretta) and Kemp's ridley (Lepiochelys kempii) sea turtles, blue-dyed bait is not effective in reducing olive ridley (Lepidochelys olivacea) and green sea turtle (Chelonia mydas) bycatch in longline fisheries in Costa Rica.

18/0 circle hooks when compared with J hooks significantly reduce loggerhead (Caretta caretta) and leatherback (Dermocheles coriacea) sea turtle bycatch in Atlantic longline fisheries for pelagic swordfish (Xiphias gladius). Circle hooks also reduced the rate of hook ingestion by loggerhead sea turtles. The combination of circle hooks and mackerel (Scomber scombrus) bait was the most effective in reducing sea turtle bycatch and had no negative effect on swordfish catch. Loggerhead sea turtle (Caretta caretta) bycatch in the Atlantic longline fishery increased with an increase in total soak time. Soak time was insignificant for swordfish but it was significant for bigeye tuna (Thunnus obesus).

18/0 circle hooks when compared with J hooks significantly reduce loggerhead (Caretta caretta) and leatherback (Dermocheles coriacea) sea turtle bycatch in Atlantic longline fisheries for pelagic swordfish (Xiphias gladius). Circle hooks also reduced the rate of hook ingestion by loggerhead sea turtles. The combination of circle hooks and mackerel (Scomber scombrus) bait was the most effective in reducing sea turtle bycatch and had no negative effect on swordfish catch. Loggerhead sea turtle (Caretta caretta) bycatch in the Atlantic longline fishery increased with an increase in total soak time. Soak time was insignificant for swordfish but it was significant for bigeye tuna (Thunnus obesus).

18/0 circle hooks when compared with J hooks significantly reduce loggerhead (Caretta caretta) and leatherback (Dermocheles coriacea) sea turtle bycatch in Atlantic longline fisheries for pelagic swordfish (Xiphias gladius). Circle hooks also reduced the rate of hook ingestion by loggerhead sea turtles. The combination of circle hooks and mackerel (Scomber scombrus) bait was the most effective in reducing sea turtle bycatch and had no negative effect on swordfish catch. Loggerhead sea turtle (Caretta caretta) bycatch in the Atlantic longline fishery increased with an increase in total soak time. Soak time was insignificant for swordfish but it was significant for bigeye tuna (Thunnus obesus).

Underwater setting chutes reduce bycatch of seabirds--Laysan (Phoebastria immutabilis) and Black-footed (P. nigripes) albatrosses--in the Hawaiian (U.S.) longline tuna fishery. The underwater setting techniques increased bait retention.

Acoustic alarms reduce bycatch of harbor porpoises (Phocoena phocoena) in the Gulf of Maine (United States) sink gillnet fishery. Gillnets with and without acoustic alarms caught similar quantities of target species, cod (Gadus morhua) and pollock (Pollachius virens). Acoustic alarms did not affect catch of bycaught silver hake (Merluccius bilinearis), but Atlantic herring (Clupea harengus) was caught less frequently in experimental nets with alarms. Harbour seals (Phoca vitulina) depredated fish caught in both nets with and without acoustic alarms.

Acoustic alarms reduce bycatch of harbor porpoises (Phocoena phocoena) in the Gulf of Maine (United States) sink gillnet fishery. Gillnets with and without acoustic alarms caught similar quantities of target species, cod (Gadus morhua) and pollock (Pollachius virens). Acoustic alarms did not affect catch of bycaught silver hake (Merluccius bilinearis), but Atlantic herring (Clupea harengus) was caught less frequently in experimental nets with alarms. Harbour seals (Phoca vitulina) depredated fish caught in both nets with and without acoustic alarms.

Over time, noxious bait, consisting of dead steelhead containing lithium chloride, did not prevent California sea lion (Zalophus californianus) predation of Washington (U.S.) steelhead trout (Salmo gairdneri). Acoustic harassment devices worked only for a short time in reducing California sea lion depredation before sea lions began to habituate to sounds.